The invention relates to a safety arrangement for a motor-driven, hand-held portable tool such as a chain saw or the like. The tool has a housing equipped with two handles which are grasped by the operator using both hands for holding and guiding the tool. The safety arrangement includes two switches arranged with respect to the handles, respectively. These switches must both be closed by actuating the switch contacts in order to operate the tool. One of the handles is mounted on the forward portion of the housing and is configured as a bail handle.
With a safety arrangement of this type, the operator of the tool is compelled to always grasp both handles in order to prevent accidents. For this reason, the working tool of the portable tool, for example a cutting chain, is brought immediately to rest as soon as one of the two switches is open irrespective of what occurs should the portable tool be held by only one of its handles.
U.S. Pat. No. 3,131,277 discloses a safety arrangement for a chain saw equipped with a bail-type handle. The safety arrangement includes two switches mounted on the bail-type handle, one of which is located at the upper leg of the handle and the other is located on the downwardly extending portion of the handle. In this way, each switch corresponds to a particular working position of the motor-driven chain saw. If both switches are released, a short circuit is caused so that the motor of the chain saw is disconnected. Therefore, each time that the forward handle is released, the motor must again be started. Furthermore, the operator is compelled to grasp the handle at specific locations because of the arrangement of the switches thereon. These positions, however, often do not correspond to the most desirable location for holding the portable tool during operation, so that the use of the chain saw is made more difficult.
In addition, the switch is coupled to a blocking member slidably mounted on the bail-type handle. This blocking member must be additionally actuated after actuating the switch so that the operation of the portable tool is difficult.